An impeller 1 used in a cross flow type cooling fan device of this type is conventionally formed by molding a synthetic resin and in which, as shown in FIG. 24, air blowing slits 3 are formed by a group of blades 4 around a hollow area 2 in the center of a cylindrical body. Air taken in radially from outside is sent through the air blowing slits 3 to cool the heat generated by the electric components. As the cooling air can be widely and planely sent out forming a laminar air flow, the impeller is particularly suitable for cooling the electric components disposed on a printed board.
However, because a motor 6 used for rotational driving of the impeller 1 is connected adjoiningly to the side of the impeller 1, a problem exists in that a space necessary for installing the cooling fan device is inevitably large, which is an obstacle in designing a compact electric appliance.